28728340 has 12 divisors (see below), whose sum is σ = 60329556. Its totient is φ = 11491328.

The previous prime is 28728319. The next prime is 28728341. The reversal of 28728340 is 4382782.

It can be written as a sum of positive squares in 2 ways, for example, as 13220496 + 15507844 = 3636^2 + 3938^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28728296 and 28728305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 718189 + ... + 718228.

It is an arithmetic number, because the mean of its divisors is an integer number (5027463).

Almost surely, 2^28728340 is an apocalyptic number.

28728340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28728340 is an abundant number, since it is smaller than the sum of its proper divisors (31601216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28728340 is a wasteful number, since it uses less digits than its factorization.

28728340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1436426 (or 1436424 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 28728340 is about 5359.8824613978. The cubic root of 28728340 is about 306.2693315577.

The spelling of 28728340 in words is "twenty-eight million, seven hundred twenty-eight thousand, three hundred forty".